If you're building one of these object storages for yourself (say, using Ceph or OpenStack Swift), a plausible configuration is 12 drives with 8 TB each, or 96

If you're building one of these object storages for yourself (say, using Ceph or OpenStack Swift), a plausible configuration is 12 drives with 8 TB each, or 96 TB per node [1]. Let's round that to 100 TB for simplicity. You obviously want to spread your replicas across multiple datacenters, so let's just say you'll put 10 of these servers (i.e. around half a rack full) each into three different datacenters. That's a very modest deployment in terms of floor space, and yet already has a capacity in the low petabyte range (3 PB raw capacity, 1 PB net capacity). On the AWS scale, object storage servers will probably be filling entire datacenters (or at least an appreciable portion of each datacenter), so it's very easy to see them being well into the exabyte (= million terabyte) scale, though probably not zettabyte (= billion terabyte) yet. [1] Source: I help maintain an object storage for a private cloud. Disclaimer: These are not the exact numbers for our nodes, but in the same ballpark.